A patent literature 1 (Japanese Unexamined Patent Application Publication 2010-267677) discloses a semiconductor device equipped with a trench gate type Metal Oxide Semiconductor Field Effect Transistor (MOSFET). The semiconductor device includes a semiconductor substrate in which a plurality of trenches is formed, a gate electrode embedded in the trenches with a gate insulating film sandwiched therebetween, and an n-type source region, a p-type body region, and n-type drift region formed in the depth direction in that order from the surface of the substrate along the lateral side of the trenches.